For centuries, nomads from the Fulani ethnic group have driven their cattle across thousands of miles of African grazing lands, through countries including Mali, Niger, Chad, Cameroon and Nigeria. But Nigeria is Africa's most populated country. And more and more land there is being used for food production.
In the far north of Nigeria, the situation has put farmers and nomads at odds with each other. David Hecht reports from the small village of Yardanko.